EXPERIMENT STATION. 69 



Most of the ground bone that comes into market contains a 

 considerable, often a large, proportion of coarse fragments which 

 remain in the soil for years before they become of avail to plants. 

 The finest parts of ground bone are, on the other hand, adapted 

 to feed crops at once. If ground bone be treated directly with 

 sulphuric acid, the fine parts are promptly decomposed, but the 

 coarse portions are but little acted on unless a large amount of 

 acid and much time are consumed. Dr. Alexander Mliller has 

 proposed the following very rational method of treating ground 

 bone, which is the best adapted for domestic use of any of the 

 processes involving the use of the oil of vitriol. 



Take 100 lbs. of ground bone such as contains 20 to 50 per 

 cent., more or less, of material coarser than ^ inch, 25 lbs. of oil 

 of vitriol of 66°, the strongest commercial acid, and six quarts of 

 water. 



Separate the bone by sifting into two, or if the proportion of 

 coarse bone is large, into three parts, using sieves of -^ inch and 

 ^ inch mesh. 



Mix the coarser part of the bone in a cast-iron or lead-lined 

 vessel with the oil of vitriol. When the bone is thoroughly wet 

 with the strong acid, add the water, stirring and mixing well. 

 The addition of the water to the acid developes a large amount 

 ■of heat which favors the action. Let stand, with occasional stir- 

 ring, for twenty-four hours, or until the coarsest fragments of 

 bone* are quite soft ; then, if three grades of bone are used, work 

 in the next coarser portion of bone, and let stand another day or 

 two until the acid has softened all the coarse bone, or has spent 

 its action ; and finally, dry oif the mass by mixing well with the 

 finest bone. In carrying out this process, the quantity of oil of 

 vitriol can be varied somewhat — increased a few pounds if the 

 bone has a large proportion of coarse fragments, or diminished if 

 it is fine. 



Stoeckhardt gives a somewhat diflerent procedure, viz: "From 

 a mixture of sifted wood or coal ashes and earth thrown upon 

 a barn or shed floor form a circular wall, so as to enclose a pit 

 capable of containing one hundred weight of ground bone; the 

 surrounding wall of ashes may be rendered so firm as not to yield 

 by being trodden down or beaten firm with a board. 



Sift off the finer part of the bone and set it aside. Throw the 

 coarser part into the cavity, and sprinkle it during continued 

 Stirling with three quarts of water until the whole is uniformly 



